Energy bands splitting in the Kohmoto model

Abstract

Peierls gap is analyzed in case of a two-dimensional lattice under the influence of a magnetic field, in a tight-binding approximation. By using a non-analytic class of potentials, such as the Kohmoto potential in the Harper model, splitting effect occurs in the energy bands. In the metal-insulator transition point, the charge carriers become separated due to their energy, releasing and expanding the Peierls gap. As a result, the energy bands around the Fermi level become localized in case of the electrons and delocalized corresponding to the holes, since their energy become lowered. These facts are supported by numerical investigations.